First-principles study of the thermal properties of Zr2C and Zr2CO

First-principles calculations of lattice thermal conductivities and thermodynamic properties of Zr2C and Zr2CO were performed using the quasi-harmonic approximation. Oxygen in the lattice gives Zr2CO higher bonding strength than Zr2C. Thus, the mechanical properties of Zr2C are enhanced when the vacancies in its crystal structure are filled with oxygen. Among the critical parameters that determine the lattice thermal conductivity, Zr2C has significantly higher Gruneisen parameters, thus Zr2C has lower lattice thermal conductivity than Zr2CO. In addition, Zr2CO has a higher heat capacity and thermal expansion coefficient than Zr2C at most temperatures. These results indicate that the addition of oxygen has increased the stiffness and thermal conductivity of zirconium carbide that contains a large fraction of carbon vacancies due to the filling of vacancies in the Zr2C lattice and the formation of Zr-O bonds.

Automated summary

This study investigates the lattice thermal conductivities and thermodynamic properties of Zr2C and Zr2CO through first-principles calculations. The results show that filling oxygen in the lattice enhances the mechanical properties of Zr2C and reduces its lattice thermal conductivity, while Zr2CO exhibits higher heat capacity and thermal expansion coefficient.